CCBYNC Open access

Relation between volume and outcome for patients with severe sepsis in United Kingdom: retrospective cohort study

BMJ 2012; 344 doi: (Published 29 May 2012) Cite this as: BMJ 2012;344:e3394
  1. Jason Shahin, assistant professor1, clinical research associate2,
  2. David A Harrison, senior statistician2,
  3. Kathryn M Rowan, director2
  1. 1McGill University, Department of Critical Care, Department of Medicine, Respiratory Division, 1650 Cedar Avenue, Montreal, Quebec, Canada H3G 1A4
  2. 2Intensive Care National Audit & Research Centre (ICNARC), London WC1H 9HR, UK
  1. Correspondence to: J Shahin Jason.shahin{at}
  • Accepted 17 April 2012


Objective To evaluate whether a relation exists between volume and outcome for admissions with severe sepsis to adult general critical care units in the United Kingdom.

Design Retrospective cohort study using data from a pooled case mix and outcome database.

Setting Adult general critical care units participating in the case mix programme.

Participants Consecutive admissions to participating units for the years 2008-09 meeting objective, standardised criteria for severe sepsis.

Main outcome measures Mortality at ultimate discharge from acute hospital.

Results The primary exposure was volume of admissions with severe sepsis per unit per year. A multivariable logistic regression analysis, using generalised estimating equations, was used to assess the association between volume, modelled using fractional polynomials, and ultimate acute hospital mortality while adjusting for potential confounders. No relation was seen between volume and outcome for admissions with severe sepsis to adult, general critical care units in the UK. Subgroup analyses tested for interactions between the effect of volume and acute severity of illness or receipt of mechanical ventilation. No significant interactions were found.

Conclusions This study showed no relation between volume and outcome in admissions with severe sepsis treated in adult general critical care units in the UK.


  • Contributors: JS, DAH, and KMR contributed to the study design, analysis, and drafting of the manuscript. All the authors approved the final manuscript. JS is the guarantor.

  • Funding: This research received no specific funding. JS was funded through a bursary provided by the Fonds de Recherche du Québec-Santé.

  • Competing interests: All authors have completed the Unified Competing Interest form at (available on request from the corresponding author) and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationship or activities that could appear to have influenced the submitted work.

  • Ethical approval: The study had approval by the Ethics Committee at the London School of Hygiene and Tropical Medicine, and ICNARC has approval for the case mix programme database under section 251 of the NHS Act 2006 (approval No PIAG 2-10(f)/2005).

  • Data sharing: A technical appendix and the statistical code are available from the corresponding author at Jason.shahin{at}

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-commercial License, which permits use, distribution, and reproduction in any medium, provided the original work is properly cited, the use is non commercial and is otherwise in compliance with the license. See: and

View Full Text

Sign in

Log in through your institution